sugar wash trials

[mogur]

I inserted gelatin powder into the nutrient spreadsheet. What a weird bird. It has more protein than soy protein isolate, yet two of the essential amino acids are absolutely missing. In case anyone wants to look, I'm attaching a zip of the nutrient spreadsheet. Tried to export a pdf, but that just spread the whole table over 14 pages. Importing a cut and paste of the table into OpenOffice draw just locked up the program... over and over. Oh well, small cut and pastes work fine, just not a large table.

nutrient data.zip

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I will definitely give gelatin a go in trial five, though. Going to focus on various yeasts as nutrients. Almost out of wine yeast, so it's time to compare baker's yeast to wine yeast as the 'ethanolator'.

[Buccaneer Bob]

Mogur, you truly are a nutrient god!

I'm avoiding the temptation to ask you if you work in a chem lab. I don't need to know. Not going to ask.

Just, wow!

Heck, I thought I was doing good coming up with the nitrogen content of unflavored gelatin.

But I couldn't find any sort of data on stuff like magnesium anywhere on the internet.

Yeah, gelatin is weird stuff. It has a lot of amino acids/nitrogen, but it lacks other stuff that yeast really need, like B-vitamins.

It's not an all-in-one yeast nutrient, for sure, but if coupled with some other adjunct, the coupling could result in a complete nutritional system.

My plan is to use gelatin with boiled yeast trub to bump up the nitrogen content on my next rum wash. Probably going to launch that on Monday.

But I'm almost thinking a coupling of gelatin and the right multivitamin might make a pretty decent yeast nutrient system, as well ... a multivitamin or some other adjunct that is rich in the right vitamins and minerals but low in nitrogen/amino acids.

I think a lot of people would be leery of using gelatin in something they are going to distill for fear of gumming-up their stills.

But I am imagining yeast going through gelatin much like amylase enzymes go through starches.

The gelatin might threaten to gel for maybe an hour or so when it's first pitched into a wash -- still not sure how it's going to work yet, myself.

But it won't take very much more time than that before yeast have broken the gelatin down to the point where its tendency to gel has been completely thwarted.

I'm basing that on various documents that I found about fruit enzymes attacking gelatin and preventing it from gelling.

I haven't found anything specific about yeast doing the same thing, but I'm about 99% sure that the effect will be the same.

[mogur]

Grin, thank you, but I am no scientist. No lab. Left graduate school to work with my hands and became a carpenter. Then manufacturing and electronic design when I got too old to carry around a stack of lumber.

I did, though, spend months collecting and organizing nutrient data from the internet. I first found this site- http://sun.ars-grin.gov:8080/npgspub/xs ... istsp.xsql Just type in any plant, like wheat, rice, barley, or whatever. I was cutting and pasting that info into a spreadsheet where it was necessary to sort the information and average the high to low amounts in order to compare to other plants. Eventually, I stumbled across this site- http://nutritiondata.self.com/facts/cer ... sta/5743/2. Wow, that made everything easier. Just type in any food, select 100g serving size (all results have 100g size available in the list of choices). I just cut and paste that data into an entry page of my spreadsheet, manually type in the amounts (the amounts are jammed into one column with the names of the components), and shift the decimal point if necessary to convert all the numbers to milligrams.

The hard part once you have the info is deciding what is stimulative or inhibitive for yeast growth and alcohol production. In the end, it's all irrelevant without an understanding of the nutritional requirements of Saccharomyces cerevisae. The literature all claims that soybeans are great for yeast nutrition due to its high protein (and thereby nitrogen and amino acids). I found that even with vitamin supplementation from either nutritional yeast or Fermaid K (very high in thiamin), soy performed dismally for me. I cannot explain why, and it is a bit frustrating. But, I will keep marching along until I find what works for me, even if I find it by chance instead of by a complete understanding of the science.

[Buccaneer Bob]

Well I'm still quite impressed. And thanks for the links. Those are going to come in handy.

The hard part once you have the info is deciding what is stimulative or inhibitive for yeast growth and alcohol production. In the end, it's all irrelevant without an understanding of the nutritional requirements of Saccharomyces cerevisae. The literature all claims that soybeans are great for yeast nutrition due to its high protein (and thereby nitrogen and amino acids). I found that even with vitamin supplementation from either nutritional yeast or Fermaid K (very high in thiamin), soy performed dismally for me. I cannot explain why, and it is a bit frustrating. But, I will keep marching along until I find what works for me, even if I find it by chance instead of by a complete understanding of the science.

Yeah, I think one of the big deals is that the science of fermentation is evolving as quickly as the technology to understand it is evolving.

Even though men have been harnessing yeast to make alcohol for thousands of years, it's only been in the last few decades that scientists have been able to actually look inside a yeast cell to see things like how this organism uses nitrogen or why it produces ethyl acetate when it does.

And now all of us hobbyists can take the information that's being gathered by the scientists and figure out how to apply it to our home fermentations. That's where the rubber hits the road.

So some of the information that's coming at us might turn out to be a red herring, but then there is other information that's coming at us that is proving incredibly helpful when it comes to doing cleaner, more productive, and better quality fermentations that lead to tastier alcoholic beverages.

Of course, I understand that some folks prefer to keep it simple: pitch some yeast at sugar in water and see what happens. If that's how they want to go about it, super. I totally get that.

But me, I love science, anyway, so I don't mind digging a little deeper into it. I want to know all of the things that I can do to maximize the good stuff and minimize the bad stuff, even if it is only for my own personal stock of hooch, you know.

[Buccaneer Bob]

Well, I launched my latest batch of rum today using boiled yeast trub and 40 grams of unflavored gelatin in a 20 liter wash. As near as I can figure, that's about 7 grams of nitrogen total or about 350 mg/L.

I had read that 350 mg of nitrogen per liter was ideal for a 14% wash, so that was what I went with.

No gelling whatsoever, and the ferment has gone pretty much ballistic. I've never had a fermentation pumping out CO2 like this one is doing right now. It's almost a little scary.

And usually it takes me 24 hours to get my fermentation really rolling, but this time it was rolling like never before in about 2 hours.

I had been considering adding the gelatine in stages, but then I started thinking this stuff isn't like DAP, the nitrogen is tied up in amino acids, so it's going to be a slower release kind of deal than DAP.

But maybe not. It seems like the yeast have torn through the gelatin like there's no tomorrow, and now they're tearing through molasses sugars like a gazillion little Oompa Loompas.

I think on the next go-round, I will add the gelatin in stages or cut down the dosage or both, but I am going to see how this batch works out and how the rum tastes.

I'm almost wondering if it might lack some flavor if the fermentation goes too quickly, but I will know better when I start distilling.

[mogur]

He, he. Well, I will bracket that gelatin adjunct. I am planning on trying 6 grams/liter, or 120 grams/20liters, along with DAP, wheat germ, and either nutritional yeast, or hydrolysed yeast. If a little is good... why not try too much? (old yankee saying)

wash trial five.pdf

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If it turns out to be overkill, well, I like bottle rockets, too.

[Buccaneer Bob]

Looks good, mogur. So you coupled gelatin with raw wheat germ, correct?

Yeah, I have been researching yeast, proteins, amino acids, peptide chains, proteolysis, and a whole bunch of other crazy stuff lately.

But it has been shedding some light onto why autolyzed/hydrolyzed yeast works better as a nutrient than boiled yeast -- during autolyzing/hydrolyzing, the amino acids of the defunct yeast cells are being broken down to the point where live yeast are better able to take them up.

Also, I am coming to realize that the live yeast would have much better results with the gelatin I have been experimenting with if the amino acids in the gelatin were broken down with certain enzymes like papain before they are fed to the live yeast.

Apparently the yeast in my most recent rum run are having at least some success taking up the gelatin proteins, but in the future, I am thinking I need to explore using papain to break down the amino acids in both my boiled yeast trub and my gelatin.

Crazy stuff.

Yeah, I am definitely in way over my head.

[mogur]

Yeah, I'm waiting on a call back this afternoon from a scientist at 3V Comany, Inc., the importers of 'Liquid Meat Tenderizer'. I'm hoping he will give me at least a rough estimate of the papain concentration in their product. The ingredients listed are simply: triple filtered water and refined papain (derived from papaya). I just took a stab at it and hydrolysed 200 ml slurries with 10 ml of tenderizer. I could also just buy a pound of papain powder at about $50, but the idea here is to use readily available, inexpensive nutrients.

I'm two hours into trial five, just took the first weighing data. Only two of nine have lost one gram so far. But, I'll have a better idea by this afternoon. You can barely see the gelatin layer (dark areas) near the bottom of bottles 8 and 9. I ended up going with only 4g/L gelatin, and yes, they are two of the four bottles with wheat germ as well. I didn't even think about using papain on the gelatin, great idea. If they perform well, will have to try that.

In trying to get a handle on the foam problem, I wiped the inside of each bottle neck with canola oil, and used 100 ml less volume to give it a bit more headroom. That foam is both satisfying and a pain in the ass. I'm going with less satisfying and easier.

the start of trial five

Oh, and here is my lab...

tasting trial three washes after a week or so in the refrig

[Buccaneer Bob]

Very good. Yeah, I don't have any good suggestions on the foam. Supposedly their are anti-foaming agents, but that would throw off the whole test, I'm sure.

I could also just buy a pound of papain powder at about $50, but the idea here is to use readily available, inexpensive nutrients.

And you've just pointed to why this project is so near and dear to my heart.

I live in a Third World country, and we don't have brew shops on the street corner like they do in many parts of the developed world. As near as I can tell, the closest brew shop to me is well over 1,000 kilometers away.

No DAP around here, anywhere ... just urea-based fertilizers ... possibly ammonia, but, nah, not gonna trust any ammonia being sold as a cleaning product.

And there's no way in the world I would ever be able to order DAP from the US and have it arrive here, hassle free.

If I'm lucky, the government employees who open the package and inspect the contents will simply send the package back to the brew shop with a note that says: "We do not know what this is, and we do not want it in our country."

If I'm not so lucky, there will be an investigation into: "Holy crap! What is diammonium phosphate?!" and "Why does this guy need diammonium phosphate?!"

Yeah, not gonna happen.

We do have plenty of basic food stuffs, though: beans, rice, tomatoes, peas, lentils, wheat, barley, oats, corn, milk, that kind of stuff.

And we do have a few processed foods that they sell in the US and elsewhere, but only the more common stuff: yogurt, gelatin, flour, cookies, soft drinks, ice cream, that kind of stuff.

And, of course, we have tons and tons of sugar and molasses. Thank goodness for that.

Oh, and bakers yeast. We have plenty of that, too.

So, yeah, my goal is to take the molasses, sugar, yeast, water, and ... whatever I can find at the local grocery store ... to make a good, vigorous, clean rum wash and turn that into a good tasting rum.

[MDH]

Do you not have a lot of fruit in your country?

I'm just coming here to report one of my more successful sugar washes so far:

4.2kg Dextrose
19l Water Dechlorinated with 1/3 tsp Ascorbic Acid Solution
1/2 Tsp Citric Acid
1 Tablespoon Yeast Nutrients
1 lb Wheat Bran (unlike the germ, this has very little to no flavor)
15g Lalvin EC1118

I took 5l of the water and inverted the sugar with the wheat bran to incorporate the nutrients. I then diluted the rest with all the other ingredients except yeast. I warmed and pitched the yeast and fermented in a fermenting bucket for about one week at 20c. After a week I stopped fermentation by leaving the bucket outside, where it is an unbelievably friggin' cold year in the pacific northwest. I racked it off, cleared it with sparkolloid until crystal, then racked it into the still and ran a stripping run. Treated this stripping run product with 10g Copper Ascorbate and then with 50g Sodium Hydroxide solution, then added an anti boiling agent and refluxed last night.

What can I say, it's better than commercial swill right now but I haven't yet filtered and subjected the spirit to prolonged aging.

[Buccaneer Bob]

Do you not have a lot of fruit in your country?

My bad. Yeah, we have most of the fruits and vegetables that much of the developed world has -- apples, pears, oranges, peaches, plums, mandarins, limes, carrots, potatoes, celery, watermelon, etc. -- and even a few things that I had never seen before I moved here -- purple sweet potatoes, guayaba (guava), strange squashes, sapote, cherimoya, granadas (pomegranates), membrillos (quinces), etc.

Oh, and we have papaya here too, fresh year-round and reasonably priced.

Thanks for the recipe. We actually do have wheat bran here, and I definitely need to take a look into that.

[MDH]

I suspect purple sweet potatoes (Okinawan) would make a good spirit, if it hasn't been done already. I know somebody who wants to open a distillery in Hawaii and begin producing vodka from them there.

If you can, look for Guanabana (also known as Guayobano, Soursop). It makes an excellent dessert wine and I suspect the distillate would be incredible.

[Buccaneer Bob]

I suspect purple sweet potatoes (Okinawan) would make a good spirit, if it hasn't been done already. I know somebody who wants to open a distillery in Hawaii and begin producing vodka from them there.

If you can, look for Guanabana (also known as Guayobano, Soursop). It makes an excellent dessert wine and I suspect the distillate would be incredible.

Yes, we do have guanabana here, but they're kindof rare and pricey.



However, I have the cousin of guanabana, the cherimoya, growing in my backyard.



The only trouble is, it drops one single fruit every couple of days, so it's hard to accumulate enough of them to do much with. I think I picked up our last one for the season about a week or so ago, and my wife made juice out of it.

I am really interested in trying some guayaba (guava) sometime. I just love those things, and they're cheap year-round here.

[mogur]

Thank you, MDH. Wheat bran tasted great in earlier trials. I haven't tried the wheat germ taste, yet. (Of course, I'm only talking about wash taste, not final taste.) Here's my taste tests so far (page one)...

trial wash summary.pdf

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[Edit: Damn, didn't get the gelatin cost in that spreadsheet. This is getting really confusing. Tomorrow, I will do better. And the day after, even betterer. ]

[Buccaneer Bob]

Good stuff. Yeah, your taste test helps give us some idea how things might distill out.

[Edit: Damn, didn't get the gelatin cost in that spreadsheet. This is getting really confusing. Tomorrow, I will do better. And the day after, even betterer. ]

However, too much tasting is not so good for the scientist.

[mogur]

However, too much tasting is not so good for the scientist.

Come on, I left a few ml for distilling, grin.

Btw, you have some really weird fruit.

[mogur]

This trial stayed in lag phase for over 16 hours. I'm not sure why, possibly three reasons...
1. It's colder in the brewing environment now, around 64 F.
2. The yeast slurries were 15 F warmer than the washes at pitch, possibly thermo-shocking the yeast.
3. The canola oil used as an anti-foam agent may be an inhibitor of fermentation.

At any rate, it makes this run not very comparable to previous runs, since the entire group is sluggish. There is one wash that is almost identical to a trial four wash, however, so some comparisons can eventually be inferred.

This is too early for any real judgement, but here is a peek...

trial five chart early.pdf

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[Buccaneer Bob]

Yeah, that's strange about the lag-time. I wouldn't think the canola oil would be a factor. I'm leaning toward either the thermal shocking or the colder environment.

Definitely keep us posted.

[mogur]

One other difference for this run is that I dropped the Fermaid K for all bottles, using a little bit more DAP to keep the inorganic YAN just above 200 ppm. If that caused the problem, I can't tell, because I didn't do a control for it (meaning some bottles with Fermaid K, some without).

Another difference for this run is that I forgot to wear my magic jock-strap. And no, I don't plan on doing a control for it. Nor do I plan on washing it. Hey, what works, works. No superstition here.

[pounsfos]

wow what a read,

I'm trying a few things myself and seeing how we go

It's amazing what you can use though isn'tit

[DavidWatkins]

I am really interested in trying some guayaba (guava) sometime. I just love those things, and they're cheap year-round here.

Guava makes just about my favorite dessert wine.

I used to get guava paste pretty cheap at the bodega when I lived in Florida. Just guava paste (came in flat bricks or round tins) and water to make 1.120, pitch ec-1118 and wait. I'd rack to a secondary after a week and a half and add pectic enzyme. It would finish fermenting at nearly a month and I bottle in splits (375ml). I don't degas this one, the extra acidity and light carbonation improve the flavor in my opinion.

Best after a year, this yields a pink lightly sparkling wine with just a hint of sweetness and a hell of a kick.

[Buccaneer Bob]

Guava makes just about my favorite dessert wine.

I used to get guava paste pretty cheap at the bodega when I lived in Florida. Just guava paste (came in flat bricks or round tins) and water to make 1.120, pitch ec-1118 and wait. I'd rack to a secondary after a week and a half and add pectic enzyme. It would finish fermenting at nearly a month and I bottle in splits (375ml). I don't degas this one, the extra acidity and light carbonation improve the flavor in my opinion.

Best after a year, this yields a pink lightly sparkling wine with just a hint of sweetness and a hell of a kick.

Thanks, DavidWatkins. I'm definitely going to have to give that a try.

[mogur]

I know that virtually no one on this forum is going to hydrolyse yeast as a fermentation nutrient, yet in case a few are interested in the subject, here is an example of my current method-

My next trial run will require 12 g/L of hydrolysed baker's ADY in three 1.5 liter bottles. So I want to start with a 20% (w/v) slurry of yeast to water, and 60 grams of yeast mixed into 300 ml of tap water will give me enough for this run. Here's the equipment:

1. Old, cheap crock pot set to lowest setting.
2. A heavy, tall glass that fits under the crock pot lid.
3. Temperature controller with remote sensor.
4. Thermometer to monitor slurry temperature.

After weighing 60 grams of ADY and 300 ml of water, I stir them together for a few minutes to dissolve all the yeast.

Plug the crock pot into the controller output, place the remote sensor probe into the bath water, and set to desired temperature. I designed and built this controller, so I'm using it, but any cheap controller should work if it can be set to 125F degrees and control 50 watts or so of 120 VAC (or whatever your crock pot requires).

Add enough bath water to the crock pot to bring the water level up to an inch or two of the top of the glass.

Set lid in place. Slowly bring temp up to about 110F, hold for a hour or two, then add an enzyme. I use 10 or 20 ml of liquid papain (unknown concentration). Now just set the temperature to 125F and leave it for about 24 hours. Fortunately, my crock pot glass lid has an easy to unscrew handle in the middle of it that allows me to monitor the slurry temperature with a cheap digital thermometer. If not, use another remote probe thermometer, or just forget it and monitor the bath water temperature with the temperature controller, the exact slurry temperature is not at all critical.

That's it. Sounds complicated, but I have this set up right next to where I spend most of my time, so it really isn't much trouble. The final product separates into a clear amber liquid above the settled drub. The last trial I did compared the upper layer of the hydrolysed ADY to the bottom layer, and I hope to wrap that up and post the results tomorrow.

[mogur]

If you need more volume than a water glass, or don't want to buy a temperature controller, this may work just as well.
Beg, borrow, or steal a yogurt maker. I found this one at a thrift store for $4.50. It included a digital thermometer that turned out to be the most accurate thermometer that I own (pure luck). The inner yogurt bucket holds more than a half gallon, so it can handle a pound or so of ADY, or two quarts of trub.

I hoped to defeat the thermostat, so I took it apart to do just that. Well, it doesn't have a thermostat. It's just some heat tape wrapped around the bath chamber, directly wired to the power cord. The temperature is supposed to reach and stay at 108-112F in an area of normal room temperature.

But, this slip of paper seems to provide for the possibility of either upping the bath temp by placing the machine in a 15F warmer area, or even just insulating the crap out of it (or putting it in a cheap ice chest). Haven't tried this out yet, but will probably be forced into it when I scale up these trials to much larger batches. On the other hand, this thing only draws 12.5 watts of power, so a few days at 110F may be enough to get sufficient autolysis/hydrolysis for mere pennies. Will try to play with that, as well.

[Buccaneer Bob]

We're not worthy! We're not worthy! We're not worthy!



I had to find the right emoticon.

Amazing stuff, mogur.

Actually, hydrolyzing yeast is most definitely on my list of things to do.

And I'm thinking there are others who will give it a go, too, once they understand the advantage to using hydrolyzed yeast as a nutrient.

[mogur]

Thank you, I am not worthy, but love ya, man.

(PS a buddy brought me some apple pie moonshine. And he claimed to have sampled Popcorn's moonshine. That's hard to believe, but who am I to ruin a perfectly good story? My god, why am I screwing with this fermentation? That was so good, it convinced that this hobby is more about distillation, and not my lame ass fermentation. Oh well, copper is my next best friend.)

[mogur]

This was a two group trial. The first five bottles were all 8g/L of various yeasts. The other four bottles were to be a combo of wheat germ and yeast with two also having gelatin, and the total adjuncts were to total 20g/L. Through operator error, one of these combos ended up with 4g/L more yeast than the others. That bottle won the race, but it cheated by having more nutrients than any of the others. 4g/L of gelatin was too much, there were globs that I had to strain out in order to take SG readings. Will pare back to 2g/L in the next run.

Hydrolysation was a much faster ferment than simply boiling the yeast. While ADY led trub (I'm using trub as shorthand for washed trub yeast) early on, half way through the ferment ADY slowed up for some reason, and trub continued to ferment at the same rate as earlier. Must be something in washed used yeast that protects the live yeast from alcohol toxicity, or provides a type of essential nutrient that ADY runs out of halfway through.

trial five chart final.pdf

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wash trial five.zip

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[Buccaneer Bob]

Very good, mogur.

Your test sure makes it clear that hydrolyzing is the best way to convert old dead yeast into a yeast nutrient for new live yeast.

Yeah, I came across this recently:

Yeast growth requires the uptake of nitrogen for the synthesis of protein and other nitrogenous components of the cell, but yeasts can only utilize low molecular weight nitrogenous materials such as inorganic ammonium ion, urea, amino acids and small peptides. The yeast cannot take up proteins or break down peptides larger than tripeptides.

Obviously, this kind of stuff is a little heady for most of us home brewers/distillers. But in a nutshell, yeast need their nitrogen in "bite sized pieces", if you will.

Simply boiling old dead yeast may explode the old yeast cells and release the B-vitamins and whatnot inside, but it tends to leave the proteins intact, so the nitrogen inside the proteins remains largely unusable by the new live yeast.

Meanwhile, hydrolyzing old dead yeast breaks down the cells and releases the B-vitamins and whatnot inside (much like boiling) but it also breaks down the old dead yeast's proteins into "bite sized pieces" so that the new live yeast can take them up, grab that nitrogen, and run with it.

I almost wish we could do a breakout thread on the benefits of hydrolyzing yeast for nutrients, as opposed to boiling it, because that particular topic seems to be taking on a life of its own, at least for me.

[mogur]

I am glad the washed trub yeast did so well in run five. It is available to everyone and best of all, free. The clear supernatant looks like watered down Marmite, without the excess salt, and I assume is very similar to the 'yeast extract' that culture labs use. The cloudy, settled part of the ADY hydrolysate slowed down in the middle of the ferment also, but then took off again. It is obvious that the settled part of the hydrolysate contains some factor that aids fermentation in the late stages. It may well be very similar to the 'peptone' that labs also often use. In addition to bite-size pieces of protein, like yeast extract, it also contains the remnants of the cell walls, and, like yeast hulls, provides the lipids that yeast cannot produce without oxygen in the late stages of fermentation. But, I am not hypothesizing, just making uneducated guesses, here.

http://www.bdbiosciences.com/documents/ ... lysate.pdf

I think this experiment has almost run its course. I will probably do just one more nine bottle run. Any suggestions would be appreciated. Here is what I am currently thinking might be helpful to try-

wash trial six - setup.pdf

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ADY is cheap, and trub is free, so I'm upping the yeast and decreasing the grain. Thanks to MDH's mention of wheat bran's mild taste, I am going with it instead wheat germ- a little less protein, but cheaper. One more stab at gelatin in hopefully a quantity that won't congeal. In case the lack of Fermaid K nutrient was responsible for the sluggish performance of run five, I want to try no inorganic nitrogen vs. DAP only vs. a combo of DAP and Fermaid K. There didn't seem to be any obvious difference in fermentation yeasts, so I'm just going to use baker's yeast for all bottles.

Oh yeah, I also thought I would just boil up some whole trub, which I am calling 'dregs' to distinguish it from the washed trub yeast of run five. Probably a waste of time, but who knows?

[FruitsNNuts]

Kudos to you Mogur,
This is one of the best threads I've seen anywhere.

I love the simplicity of a modified BW recipe. Sugar, Old Traub, Tomato Paste, and vitamin C (to add acidity and clear out the chloramine in my H2O), make my standard, fool resistant wash. Best of all it works real good.

Your thread has awakened me to the possibility of autolyzing my yeast with a bit of salt.
http://en.wikipedia.org/wiki/Yeast_extr ... yzed_yeast" onclick="window.open(this.href);return false;" rel="nofollow
It sounds like, add a bit of salt, then cook some of you old traub to add back to the next ferment. Maybe that is exactly what young yeast would want most, (Cannibals, eat your old) in the exact proportions that they would want it. It do worry about adding salt though.

I'm going to try it, does anyone know how much salt I could add to a 25L wash before it becomes a problem?